1. Field of the Invention
The present invention relates to an antenna for a portable terminal, and more particularly, to an antenna for a portable terminal, in which an antenna occupying a relatively large area can be efficiently installed without increasing the volume of the terminal.
2. Background of the Prior Art
With the rapid spread of portable terminals, terminal manufacturers have made an effort to produce slim and lightweight terminals having various functions so as to satisfy users' demands. For example, the user can take a photograph using a small-sized camera module mounted on the terminal and can listen to music using an MP3 player mounted on the terminal. These functions cause the terminal to increase in volume due to the installation of the corresponding devices. Terminal manufacturers have made many efforts to solve these problems and implement various additional functions.
Among the additional functions of the terminal, a near field communication (NFC) technology has become commercialized. Recently, terminals having a 2.4-GHz Bluetooth™ function for NFC have been introduced. Examples of the Bluetooth™ function include data communication between terminals, and wireless communication between an ear microphone and a terminal. To perform the above-described Bluetooth™ function, a Bluetooth™ chip must be mounted on the terminal and a radiator must also be installed in the terminal.
The Bluetooth™ radiator must be separated from an RF radiator used for data transmission and reception. For example, the Bluetooth™ radiator is mounted on an RF board in a Surface Mount Device (SMD) type. A chip antenna and a plate type monopole antenna have been widely used as the Bluetooth™ radiator.
Also, terminals having the NFC function for electronic payment, Peer-to-Peer (P2P) communication, and a card reader function have been introduced. The above-described NFC function must use separate devices, and a separate antenna (other than an antenna radiator for communication) is used for an RF communication with a payment device. To use the above-described NFC function, it is necessary to mount smart Integrated Circuits (ICs), Oscillators (OSCs), and other passive elements on a main board of the terminal. Also, a low-frequency (about 13.56 MHz) antenna radiator for NFC is required. Since the low-frequency antenna radiator is bulky (about 30 mm×50 mm), it has been generally built in a battery pack of the terminal. In addition, since the NFC antenna is bulky, it is installed over an entire rear surface of the battery pack that is a power supply of the terminal. Therefore, an expensive ferrite layer must be used for avoiding the interference between the antenna and the conductive battery cell.
Therefore a separate antenna in addition to an existing antenna for communication, must be installed in the Bluetooth™ antenna or NFC antenna radiator, thus increasing the size of the terminal. Consequently, the conventional antenna does not satisfy the trend toward slim profile, lightweight and multi-function portable terminal.